Is this an alternator problem?

[KB5.0GT]

Hi there, I have a drained battery problem on my 1995 GT and I was hoping you guys could point me in the right direction. Two days ago I took my car out and I noticed that my volts were rising as my rev's were. For example over 3,000 rpm my voltage would raise to about 16v to about 17 at 4,500ish. When my volts would spike my battery light would come on.

So the next day my car ran fine, solid voltage all day.

Then this morning my battery was completely drained. After jumping it the same voltage spike was happening and the battery will not stay charged. I think my alternator is done for.

What do you guys think the problem is, and how should I fix it? Thanks for your help.

 

[mo_dingo]

Hi there, I have a drained battery problem on my 1995 GT and I was hoping you guys could point me in the right direction. Two days ago I took my car out and I noticed that my volts were rising as my rev's were. For example over 3,000 rpm my voltage would raise to about 16v to about 17 at 4,500ish. When my volts would spike my battery light would come on.

So the next day my car ran fine, solid voltage all day.

Then this morning my battery was completely drained. After jumping it the same voltage spike was happening and the battery will not stay charged. I think my alternator is done for.

What do you guys think the problem is, and how should I fix it? Thanks for your help.

Sounds like the voltage regulator in the alternator is shot. When the voltge spikes, check the voltage at the main lug on the back of the alternator. If it's higher than 14.4V your regulator is shot. Part no. FF169D from checker and it looks like they stock it.
Scott

 

[HISSIN50]

I agree with Scott. I'd add one more thing to check - the sense wire. Because the issue comes and goes, a bad connection with this wire can cause the alternator to freak out.

 

[KB5.0GT]

Thanks alot for your help. I'll work on fixing it tommarrow.

 

[94-302-vert]

If the batttery is not holdign the charge, battery....

If the battery is bad enough the alternator will try to overvoltage to charge it...

I vote battery...